For a number years now, grain has been deposited directly onto a suitable base, usually formed of blacktop or concrete, with the grain being piled in a very large conical pile with the grain being allowed to repose at its natural angle of repose. The grain is formed into such a conical pile by being dropped downwardly at a top central portion of the pile from a filling conveyor. The grain is dropped beneath a flexible cover laid on the pile. As the grain piles grows, the cover increasingly takes on its shape an is pulled upwardly at the center and takes on a more conically shape. After the pile has been completed, the central portion of the cover is secured to a central pole or tower and the lower peripheral edge is secured to a retaining like extending about the lower periphery of the conical pile. Typically, the retaining wall is an inclined wall which has air openings, which allow air to flow through the wall, the wall usually being five or six feet in height. The lower peripheral portion of the flexible cover, which is usually made of the vinyl or some canvass-like material is secured to the retaining wall. Various ways of aerating the corn or other grain which is in the pile is provided to assure that there is removable of moisture to aid in preventing spoilage.
A number of problems have been encountered when the formation of such grain piles using the flexible cover for the storage of the grain, one of which is to provide an even distribution of the granular material to keep the pile more conical. Typically, the system may include a central tower or pole with a filling conveyor extending from beyond the periphery of the retaining wall to the central tower. The filling conveyor may be a drag or screw conveyor, a gravity spout, or a portable vacuum or other various types of loading devices. Because of the large size of the grain storage which may be three hundred thousand to several million bushels of corn; for instance, the grain is often delivered to a dump pit, which is a drive-over type or a dump-hopper type from which the grain is removed and fed by the filling conveyor to the top of the pile. Because the covers are loose and the filling may take place over several days, there is often a danger of rain storms or wind storms which may loosen the cover or otherwise cause problems with rain water getting under the cover and wetting the grain.
It has been found that the discharge from the filling conveyor does not really provide a very uniform distribution of the granular material to form the conical shape. Often there was a requirement of a considerable amount of manual labor to try to move the grain to make it stack and fill evenly about the tower at the desired angle of repose as the grain at the center became higher and higher. The conveyor generally seems to want to provide more grain to one side or one area than to another side or area and even when the grain was attempted to be distributed more evenly, it was found that there were still minor areas in which the grain will not flow readily make a conical shape which is needed without further control of the grain flow.
The preferred embodiment of the grain storage system in uses an aeration tower which is a freestanding tower at the center of the pile to which the upper end of the filling conveyor is connected. The aeration tower serves, as its name indicates, to provide a suction tower for the pulling of air through the grain, preferably from the retaining wall and flows through the grain and into the central aeration tower for a flow downwardly to a main air duct, which is installed either on the surface or below grade and is connected to a centrifugal blower which discharges the air having been pulled through the grain mass so that there are no dead zones where the air is not being pulled through the grain. It would be preferred to use the aeration tower during the filling operation so that the grain is continuously and immediately aerated during the filling operation. Also, there is a need to hold the cover tight to the top surface of the grain pile during the filling operation so a wind storm doesn't remove it or damage the cover or let rain into the pile.
In addition to the foregoing, there is often a desire to know the condition of the grain particularly at the most inaccessible place, which is at the center bottom portion of the aeration tower. The condition of the grain at this area provides both buyer and seller with an idea of its quality.
Accordingly, a general object of the present invention is to provide a new and improved conical grain storage system having a flexible cover and an improved distributor for distributing the grain in a more even and directed way during the filling of the pile beneath the cover.
Another object of the invention is to provide a means for covering the aeration tower so it can be used during the filling operation to operate the grain and hold the cover down onto the top of the pile.
A further objection of the invention is to provide a lower portion of a aeration tower with means for extracting granular material from the center of the pile for an analysis thereof.